Re: Problems with multiple functioncalls on the outputbuffer in a ScriptProcessorNode

Hi Peter,

Can you post a jsfiddle or link to complete working example with source code? Even if this pseudo code looks ok there are many possible details in the real code that could cause a problem.

Also as a sanity check I suggest playing the source buffer from an AudioBufferSourceNode with loop = true to verify that the transients are not actually in the audio loop itself.

Best
.       .    .  . ...Joe

Joe Berkovitz
President
Noteflight LLC
+1 978 314 6271
www.noteflight.com
"Your music, everywhere."

On Feb 11, 2013, at 3:00 PM, Peter van der Noord <peterdunord@gmail.com> wrote:

> I've been looking for over 4 hours at a problem that generates quite loud ticks in my sound. I have simplified it all the way down, and i am wondering if my approach can work at all. 
> 
> What i'm trying to do is seemlessly stitch multiple audiobuffers together, using a custom ScriptProcessorNode (with access to all buffers) to write the correct samplevalues (from the correct position and the correct buffer) to the output. I've trimmed it all down to just using 1 buffer, that should seamlessly restart at the beginning, once it reaches the end.
> 
> This is in pseudocode my onaudioprocess-handler:
> 
> handleAudioProcessingEvent(event: AudioProcessingEvent): void
> {
>         // there are two cases: either the current writeloop reaches the end of the source-buffer, or it doesnt
>         
>         if(endNotReached)
>         {
>                 copySamples(bufferSize, 0, currentReadPosition);
> 
>                  // params are: 
>                  // the amount of samples to write (in this case the buffersize of the scriptprocessor)
>                  // the index to start writing in the outputbuffer
>                  // the index to start reading from the sourcebuffer (a loaded sample), which will be incremented in the writeloop in the copySamples function
>         }
>         else
>         {
>                 // the end of the source buffer will be reached in this writingloop, 
>                 // so write the remainig samples, then reset the readposition, then write the remaining amount of samples 
>                 // (so the amount of samples written equals the full buffersize of the scriptprocessor)
> 
>                 copySamples(numberOfSamplesLeftForSourceSound, 0, currentReadPosition);
>                 currentReadPosition = 0;
>                 copySamples(bufferSize - numberOfSamplesLeftForSourceSound, numberOfSamplesLeftForSourceSound, currentReadPosition);
>         }
> }
> 
> When the end is not reached, everything runs ok (although i have the feeling i hear some small irregularities now and then), but when the end is reached (2nd part of the if-statement), there's some big ticks in the audiostream.
> 
> I am wondering if passing the outputbuffer to two functioncalls (both partially writing in it) has anything to do with it, or that i'm overlooking something else.
> 
> 
> Peter
>